Comparators can be used as 1 bit analog to digital converters (ADCs), which may serve for example as demodulators in RFID transponders. Generally, the comparator's signal input amplitudes can vary substantially thereby affecting the integrity of the comparison result. A rather sensitive comparator may respond to a signal input that is near to the decision threshold by an undesired change of the output signal whereas a rather robust comparator may not respond to input signal changes in a sufficiently sensitive manner. Variable sensitivity can be achieved with a comparator that has an adjustable hysteresis. The hysteresis of a comparator is a function of the current through the input stage of the comparator. Accordingly, the current through the input stage is varied. This is performed stepwise with a switchable load, which is coupled to the input stage, a principle that is only applicable as long as the supply voltage range of the comparator and the modulation depth of the signal are large and the steps are acceptable. However, for up-to-date technologies the supply voltage is reduced and the conventional comparator architectures are inappropriate.